Butyrophenones: characteristics of atypical antipsychotics

The discovery of the first antipsychotic in the early 1950s, chlorpromazine, was a great revolution in the treatment of psychoses, especially schizophrenia.

In this article we will talk about a family of antipsychotics: the butyrophenones. Within it we find haloperidol (especially known for its usefulness in schizophrenia) and droperidol.

• Related article: "Types of antipsychotics (or neuroleptics)"

History: the first antipsychotic

The beginning of the investigation of butyrophenones begins with chlorpromazine.

Chlorpromazine was synthesized as an antihistamine by the French pharmaceutical industry and in 1950, Henri Laborit, a French surgeon, highlighted its sedative effect in psychotic patients. Two years later, in 1952, Delay, Deniker and Harl tested it at the Sainte Anne Hospital in Paris and confirmed its usefulness for the positive psychotic symptoms of schizophrenia.

Since the introduction of the first typical antipsychotic, neuroleptic research has focused on increasing the effectiveness of these in schizophrenia, reduce the negative symptoms of the disorder and define its mechanism of action.

Typical and atypical antipsychotics

Typical or first generation antipsychotics have more side effects than second generation or atypical ones. The latter appeared with the discovery of Clozapine in the 70s, which began to be marketed in Switzerland and Austria.

At present there are already second-generation or atypical antipsychotics, which also act on the negative symptoms of schizophrenia (something that the first generation did not do), as well as on the positive symptoms.

Their antipsychotic efficacy is similar to that of the typical ones, and they differ from them by presenting lower incidence of EPS (Extrapyramidal Syndrome: set of motor symptoms) and of hyperprolactinemia. (side or adverse effects).

butyrophenones

Butyrophenones are a family of atypical antipsychotics. Antipsychotics are a type of medication or drugs that are used to treat schizophrenia and other psychotic disorders, as well as bipolar disorder, among others.

In general, antipsychotics reduce dopamine (DA), a brain neurotransmitter abnormally high in psychotic disorders.

• You may be interested in: "Psychoactive drugs: drugs that act on the brain"

droperidol

One of the butyrophenone-type antipsychotics is Droperidol, very short-acting and strongly sedative and tranquilizing.

Droperidol has a high antiemetic activity (prevents vomiting and nausea). It acts as an antagonist of dopamine receptors, being partially selective for D2 receptors.

Its antiemetic action is produced by the antagonism of the DA receptors in a very specific area of ​​the vagus nerve. It is especially useful for the prevention and treatment of nausea and vomiting that are postoperative and/or induced by opioid analgesics.

It also exhibits weak cholinergic receptor antagonist activity. (acetylcholine) muscarinics. Acetylcholine is a neurotransmitter involved in the transmission of nerve impulses and movement.

Characteristics

Droperidol is used for the prevention and treatment of postoperative nausea and vomiting in adults, and second-line, in children and adolescents. Also for vomiting and nausea induced by morphine derivatives.

Regarding the route of administration of this type of butyrophenone, it is done intravenously.

Some of its contraindications are: cases of hypersensitivity to the drug or allergy to butyrophenones, bradykinesia (decrease in normal heart rate) and Parkinson's disease.

Precautions

It should be taken into account that it is a drug that can increase the depression of the CNS produced by other depressant drugs. Besides, caution should be taken in cases of epilepsy, hypotension, cardiac arrhythmias and chronic alcoholism, among others. The onset of unexplained fever may be a symptom of neuroleptic malignant syndrome.

The dose in the elderly should be reduced, as well as in those subjects with renal insufficiency and/or hepatic insufficiency. In patients with breast cancer or prolactin-dependent tumors, it can increase the levels of this hormone.

Haloperidol: another type of butyrophenone

Another of the butyrophenone-type neuroleptics is Haloperidol.

It acts the same as the previous one, so it is also a potent antagonist of brain dopaminergic receptors. It is classified among the highly potent neuroleptics. It has no antihistamine or anticholinergic activity (therefore no side effects of these two types).

The therapeutic indications for haloperidol are diverse. As a neuroleptic it is used in:

• Delusions and hallucinations (schizophrenia, Korsakoff syndrome…).
• Personality disorder: paranoid, schizoid, schizotypal, borderline...

As a treatment for psychomotor agitation, some of its uses are for:

• Mania, dementia, intellectual disability, alcoholism.
• Personality disorders.
• agitation, aggressiveness.
• Behavioral disorders.
• Tics, stuttering, symptoms of Tourette Syndrome...

Like Droperidol, as an antiemetic it prevents vomiting and nausea of ​​various aetiology.

It is contraindicated in cases of hypersensitivity to the drug, coma, central nervous system depression due to alcohol or other depressants, Parkinson's disease, and basal ganglia injury.

Bibliographic references:

• Ortiz, A., De la Mata, I. (2001). New Antipsychotics, 25(1), 1-8. National system of health.
• General Council of Official Colleges of Pharmacists. (2012). Drug Catalog. Council Collection.
• Inchauspe, J.A. and Valverde, M.A. (2018). Believing in clozapine: faith and evidence. Rev. Assoc. Esp. Neuropsiq, 38(133), 239-262.